ABSTRACT: Local population dynamics of fishes on coral reefs are dependent on processes affecting the settlement of pelagic larvae and the subsequent persistence of these new settlers. The ability of larvae to choose favourable places to settle in terms of persistence may make the dynamics of certain populations predictable at the reef scale, and cause patterns of recruitment to differ from those of larval supply. I collected data on settlement, recruitment and persistence of the ocean surgeonfish Acanthurus bahianus in different physiographic zones of the Tague Bay reef, on the island of St. Croix, U.S. Virgin Islands. There was significantly higher settlement and recruitment to the back-reef zone than to the fore-reef zone or seagrass zones at the bases of the back-reef and fore-reef, suggesting that larvae select settlement sites and do not necessarily settle to the first reef zone encountered. On the back-reef, settlers used pavement more than any other type of substratum, and the post-settlement persistence of settlers and recruits was highest on pavement when compared to these other substrata. These results suggest that patterns of ocean surgeonfish settlement are affected by reef-based processes, and that selection for certain zones and substrata occurs. Subsequent modification of these initial settlement patterns by increased persistence in preferred habitats adds predictability to patterns of recruitment, resulting in larval supply alone being an insufficient explanation of the distribution and abundance of ocean surgeonfish populations at this scale.

KEY WORDS: Coral reef fish · Caribbean · Otoliths · Habitat selection · Recruitment · Growth · Persistence

Published in MEPS Vol. 161 (1997) on December 31
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 1997